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  • bq24715 2-3 Cell NVDC-1 Battery Charger Controller with Ultra-Fast Transient Response and High Light-Load Efficiency

    • SLUSBD1B MARCH   2013  – September 2016

      PRODUCTION DATA.  

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  • bq24715 2-3 Cell NVDC-1 Battery Charger Controller with Ultra-Fast Transient Response and High Light-Load Efficiency
  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Pin Configuration and Function
  5. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements
    7. 5.7 SMBus Timing Characteristics
    8. 5.8 Typical Characteristics
  6. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Switching Frequency Adjust
      2. 6.3.2  High Accuracy Current Sense Amplifiers
      3. 6.3.3  Charger Timeout
      4. 6.3.4  Input Over-Current Protection (ACOC)
      5. 6.3.5  Converter Over-Current Protection
      6. 6.3.6  Battery Over-Voltage Protection (BATOVP)
      7. 6.3.7  System Over-Voltage Protection (SYSOVP)
      8. 6.3.8  Thermal Shutdown Protection (TSHUT)
      9. 6.3.9  Adapter Over-Voltage Protection (ACOVP)
      10. 6.3.10 Adapter Detect and ACOK Output
      11. 6.3.11 ACFET/RBFET Control
      12. 6.3.12 DPM
      13. 6.3.13 Buck Converter Power up
    4. 6.4 Device Functional Modes
      1. 6.4.1 LDO Mode and Minimum System Voltage
      2. 6.4.2 PWM Mode Converter Operation
      3. 6.4.3 Continuous Conduction Mode (CCM)
      4. 6.4.4 Discontinuous Conduction Mode (DCM)
      5. 6.4.5 PFM Mode
      6. 6.4.6 Learn Mode
      7. 6.4.7 IDPM Disable at Battery Removal
    5. 6.5 Programming
      1. 6.5.1 SMBus Communication
        1. 6.5.1.1 SMBus Interface
          1. 6.5.1.1.1 Write-Word Format
          2. 6.5.1.1.2 Read-Word Format
        2. 6.5.1.2 SMBus Commands
        3. 6.5.1.3 Setting Charger Options
        4. 6.5.1.4 Setting the Charge Current
        5. 6.5.1.5 Setting the Max Charge Voltage
        6. 6.5.1.6 Setting the Minimum System Voltage
        7. 6.5.1.7 Setting Input Current
  7. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Inductor Selection
        2. 7.2.2.2 Input Capacitor
        3. 7.2.2.3 Output Capacitor
        4. 7.2.2.4 Power MOSFETs Selection
        5. 7.2.2.5 Input Filter Design
      3. 7.2.3 Application Curves
  8. 8 Power Supply Recommendations
  9. 9 Layout
    1. 9.1 Layout Guidelines
    2. 9.2 Layout Example
  10. 10Device and Documentation Support
    1. 10.1 Third-Party Products Disclaimer
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Community Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  11. 11Mechanical, Packaging, and Orderable Information
  12. IMPORTANT NOTICE

Package Options

Mechanical Data (Package|Pins)
  • RGR|20
    • MPQF239A
Thermal pad, mechanical data (Package|Pins)
  • RGR|20
    • QFND242E
Orderable Information
  • slusbd1b_oa
  • slusbd1b_pm
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DATA SHEET

bq24715 2-3 Cell NVDC-1 Battery Charger Controller with Ultra-Fast Transient Response and High Light-Load Efficiency

1 Features

  • 6-24V Input SMBus NVDC-1 2-3S Battery Charger Controller
  • System Instant-on Operation with No Battery or Deeply Discharged Battery
  • Ultra-Fast Transient Response of 100 µs
  • Ultra-Low Quiescent Current of 500 µA and High PFM Light Load Efficiency 80% at 20mA load to Meet Energy Star and ErP Lot6
  • Switching Frequency: 600kHz/800kHz/1MHz
  • Programmable System/Charge Voltage (16 mV/step), Input/Charge Current (64 mA/step) with High Accuracy
    • ±0.5% Charge Voltage Regulation
    • ±3% Input/Charge Current Regulation
    • ±2% 40x Input/16x Discharge Current Monitor Output
  • Support Battery LEARN Function
  • Maximize CPU Performance with Deeply Discharged Battery or No Battery
  • Integrated NMOS ACFET and RBFET Driver
  • 20-pin 3.5 x 3.5 mm2 QFN Package

2 Applications

  • Ultrabook, Notebook, and Tablet PC
  • Industrial and Medical Equipment
  • Portable Equipment

3 Description

The bq24715 is a NVDC-1 synchronous battery charge controller with low quiescent current, high light load efficiency for 2S or 3S Li-ion battery charging applications, offering low component count.

The power path management allows the system to be regulated at battery voltage but does not drop below the programmable system minimum voltage.

The bq24715 provides N-channel ACFET and RBFET drivers for the power path management. It also provides driver of the external P-channel battery FET. The loop compensation is fully integrated.

The bq24715 has programmable 11-bit charge voltage, 7-bit input/charge current and 6-bit minimal system voltage with very high regulation accuracies through the SMBus communication interface.

The v monitors adapter current or battery discharge current through the IOUT pin allowing the host to throttle down CPU speed when needed.

The bq24715 provides extensive safety features for over current, over voltage and MOSFET short circuit.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
bq24715 VQFN (20) 3.50 mm × 3.50 mm
  1. For all available packages, see the orderable addendum at the end of the datasheet.

Simplified Application Diagram

bq24715 typ_appdiagram_lusbd1.gif

4 Pin Configuration and Function

RGR Package
20-Pin VQFN
(Top View)
bq24715 pinout_lusbd1.gif

Pin Descriptions

PIN NAME I/O DESCRIPTION
1 ACN I Input current sense resistor negative input. Place an optional 0.1µF ceramic capacitor from ACN to GND for common-mode filtering. Place a 0.1µF ceramic capacitor from ACN to ACP to provide differential mode filtering.
2 ACP I Input current sense resistor positive input. Place a 1µF ceramic capacitor from ACP to GND for common-mode filtering. Place a 0.1µF ceramic capacitor from ACN to ACP to provide differential-mode filtering.
3 CMSRC I ACDRV charge pump source input. Place a 4kΩ resistor from CMSRC to the common source of ACFET (Q1) and RBFET (Q2) limits the in-rush current on CMSRC pin.
4 ACDRV O Charge pump output to drive both adapter input n-channel MOSFET (ACFET) and reverse blocking n-channel MOSFET (RBFET). ACDRV voltage is 6.1V above CMSRC when voltage on ACDET pin is higher than 2.4V, voltage on VCC pin is above UVLO but lower than 26V and voltage on VCC pin is 675mV above voltage on SRN pin so that ACFET and RBFET can be turned on to power the system by AC adapter. Place a 4kΩ resistor from ACDRV to the gate of ACFET and RBFET limits the in-rush current on ACDRV pin.
5 ACOK O AC adapter detection open drain output. It is pulled HIGH to external pull-up supply rail by external pull-up resistor when voltage on ACDET pin is above 2.4V, VCC above UVLO but lower than 26V and voltage on VCC pin is 675mV above voltage on SRN pin, indicating a valid adapter is present to start charge. If any one of the above conditions can not meet, it is pulled LOW to GND by internal MOSFET. Connect a 10kΩ pull up resistor from ACOK to the pull-up supply rail.
6 ACDET I Adapter detection input. Program adapter valid input threshold by connecting a resistor divider from adapter input to ACDET pin to GND pin. When ACDET pin is above 0.6V and VCC is above UVLO, REGN LDO is present, ACOK comparator and IOUT are both active.
7 IOUT O Buffered 40 times adapter or 16 times discharge current output - the differential voltage across sense resistor; selectable with SMBus command ChargeOption(). Place a 100pF or less ceramic decoupling capacitor from IOUT pin to GND.
8 SDA I/O SMBus open-drain data I/O. Connect to SMBus data line from the host controller or smart battery. Connect a 10kΩ pull-up resistor according to SMBus specifications.
9 SCL I SMBus open-drain clock input. Connect to SMBus clock line from the host controller or smart battery. Connect a 10kΩ pull-up resistor according to SMBus specifications.
10 CELL I Cell selection pin. For bq24715, set CELL pin Float for 2-cell, and HIGH for 3-cell. Pulling CELL to GND will provide a hardware exit function from LEARN mode, disable the input DPM function, reset the bit[5] and bit[1] in chargeoption(), and reset Maxchargevoltage() to previous CELL pin default setting value and chargecurrent() to zero. Release CELL from GND, charger will recheck CELL pin voltage and lock the new CELL pin selection.
11 BATDRV O P-channel battery FET gate driver output. This pin can go high to turn off the battery FET, go low to turn on the battery FET, or operate battery FET in linear mode to regulate the minimum system voltage when battery is depleted. Connect the source of the BATFET to the system load voltage node. Connect the drain of the BATFET to the battery pack positive node. There is an internal pull-down resistor of 50k on BATDRV to ground.
12 SRN I Charge current sense resistor negative input. SRN pin is for battery voltage sensing as well. Connect SRN pin with a 0.1µF ceramic capacitor to GND for common-mode filtering and connect to current sensing resistor. Connect a 0.1µF ceramic capacitor between current sensing resistor to provide differential mode filtering.
13 SRP I Charge current sense resistor positive input. Connect a 0.1µF ceramic capacitor between current sensing resistor to provide differential mode filtering.
14 GND I IC ground. On PCB layout, connect to analog ground plane, and only connect to power ground plane through the power pad underneath IC.
15 LODRV O Low side power MOSFET driver output. Connect to low side n-channel MOSFET gate.
16 REGN O Linear regulator output. REGN is the output of the 6V linear regulator supplied from VCC. The LDO is active when voltage on ACDET pin is above 0.6V and voltage on VCC is above UVLO. Connect a 1µF ceramic capacitor from REGN to GND.
17 BTST I High side power MOSFET driver power supply. Connect a 0.047µF-0.1µF capacitor from BTST to PHASE. Connect a bootstrap Schottky diode from REGN to BTST.
18 HIDRV O High side power MOSFET driver output. Connect to the high side n-channel MOSFET gate.
19 PHASE I High side power MOSFET driver source. Connect to the source of the high side n-channel MOSFET.
20 VCC I Input supply. Use 10Ω resistor and 1µF capacitor to ground as low pass filter to limit inrush current.
PowerPAD™ I Exposed pad beneath the IC. Analog ground and power ground star-connected only at the PowerPad plane. Always solder PowerPad to the board, and have vias on the PowerPad plane connecting to analog ground and power ground planes. It also serves as a thermal pad to dissipate the heat.

5 Specifications

5.1 Absolute Maximum Ratings(1)(2)

over operating free-air temperature range (unless otherwise noted)
MIN MAX UNIT
Voltage range SRN, SRP, ACN, ACP, CMSRC, VCC –0.3 30 V
PHASE –2.5 30
ACDET, SDA, SCL, LODRV, REGN, IOUT, ACOK, CELL –0.3 7
LODRV (20ns) –2.5 7
BTST, HIDRV, ACDRV –0.3 36
HIDRV (20ns) –2.5 36
BATDRV –0.3 30
Maximum difference voltage SRP–SRN, ACP–ACN –0.5 +0.5 V
Junction temperature, TJ –40 155 °C
Storage temperature, Tstg –55 155 °C
(1) Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) All voltages are with respect to GND if not specified. Currents are positive into, negative out of the specified terminal. Consult Packaging Section of the data book for thermal limitations and considerations of packages.

5.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins(1) ±2000 V
Charged device model (CDM), per JEDEC specification JESD22-C101, all pins(2) ±500 V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

5.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN MAX UNIT
Voltage range SRN, SRP, ACN, ACP, CMSRC, VCC 0 24 V
PHASE –2 24 V
ACDET, SDA, SCL, LODRV, REGN, IOUT, ACOK, CELL 0 6.5 V
BTST, HIDRV, ACDRV 0 30 V
BATDRV –0.3 16 V
Maximum difference range SRP–SRN, ACP–CAN –0.2 0.2 V
TJ Junction temperature range –20 125 °C
TA Operating free-air temperature range –20 85 °C

5.4 Thermal Information

THERMAL METRIC(1) bq24715 UNIT
RGR Package (QFN)
20 PINS
RθJA Junction-to-ambient thermal resistance 34.6 °C/W
RθJCtop Junction-to-case (top) thermal resistance 49.3 °C/W
RθJB Junction-to-board thermal resistance(2) 12.5 °C/W
ψJT Junction-to-top characterization parameter 0.5 °C/W
ψJB Junction-to-board characterization parameter 12.7 °C/W
RθJCbot Junction-to-case (bottom) thermal resistance 1 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report (SPRA953).
(2) The junction-to-board thermal resistance is obtained by simulating in an environment with a ring cold plate fixture to control the PCB temperature, as described in JESD51-8.

5.5 Electrical Characteristics

6V ≤ VVCC ≤ 24V, –20°C ≤ TJ ≤ 125°C, typical values are at TA = 25°C, with respect to GND (unless otherwise noted)
PARAMETER TEST CONDITION MIN TYP MAX UNIT
INPUT OPERATING CONDITIONS
VVCC_OP VCC Input Voltage Operating Range 6 24 V
MIN SYSTEM VOLTAGE REGULATION (0x3E register)
VSYSMIN_RNG MinSystem Voltage Regulation Range 4.096 14.5 V
VSYSMIN_REG and VSYSMIN_REG_ACC Default minimum system voltage and accuracy at charge enable and battery voltage lower than VSYSMIN_REG MinsystemVoltage() = 0x2400H (3S) 9.216 V
–2% 1.2%
MinsystemVoltage() = 0x1800H (2S) 6.144 V
–3% 1.5%
MAX SYSTEM VOLTAGE REGULATION (0x15 register charge disable)
VSYSMAX_RNG MaxSystem Voltage Regulation Range 4.096 14.5 V
VSYSMAX_REG and VSYSMAX_REG_ACC Default maximum system voltage and accuracy at charge disable MaxChargeVoltage() = 0x34C0H (3S) 13.504 V
–2% 1.2%
MaxChargeVoltage() = 0x2330H (2S) 9.008 V
–3% 1.5%
MAX CHARGE VOLTAGE REGULATION (0-85C; 0x15 register charge enable)
VBAT_REG_RNG Battery voltage range 4.096 14.5 V
VBAT_REG_ACC Charge voltage regulation accuracy MaxChargeVoltage() = 0x3130H 12.529 12.592 12.655 V
–0.5% 0.5%
MaxChargeVoltage() = 0x20D0H 8.35 8.4 8.45 V
–0.6% 0.6%
CHARGE CURRENT REGULATION (0-85C)
VIREG_CHG_RNG Charge current regulation differential voltage range RSNS = 10mΩ VIREG_CHG = VSRP - VSRN 0 81.28 mV
ICHRG_REG_ACC Charge current regulation accuracy
10mΩ current sensing resistor, VBAT>VSYSMIN		 ChargeCurrent() = 0x1000H 3937 4096 4219 mA
–3% 3%
ChargeCurrent() = 0x0800H 1946 2048 2150 mA
–5% 5%
ChargeCurrent() = 0x0400H 921 1024 1127 mA
–10% 10%
ChargeCurrent() = 0x0200H 410 512 614 mA
–20% 20%
ChargeCurrent() = 0x0180H 288 384 480 mA
–25% 25%
ChargeCurrent() = 0x0100H 172 256 340 mA
–33% 33%
ChargeCurrent() = 0x00C0H 115 192 269 mA
–40% 40%
ChargeCurrent() = 0x0080H 64 128 192 mA
–60% 60%
PRECHARGE CURRENT REGULATION (0-85C)
IPRECHRG_REG_ACC Charge current regulation accuracy 10mΩ current sensing resistor,
VBAT<VSYSMIN, chargeoption(2)=1		 ChargeCurrent() >= 0x0180H 268.8 384 499.2 mA
–30% 30%
ChargeCurrent() = 0x0100H 153.6 256 358.4 mA
–40% 40%
ChargeCurrent() = 0x00C0H 96 192 288 mA
–50% 50%
ChargeCurrent() = 0x0080H 25.6 128 230.4 mA
–80% 80%
INPUT CURRENT REGULATION
VDPM_REG_RNG Input current regulation differential voltage range RAC = 10mΩ VIREG_DPM = VACP – VACN 0 80.64 mV
IDPM_REG_ACC Input current regulation accuracy 10 mΩ current sensing resistor InputCurrent() = 0x1000H 3973 4096 4219 mA
–3% 3%
InputCurrent() = 0x0800H 1946 2048 2150 mA
–5% 5%
InputCurrent() = 0x0400H 870 1024 1178 mA
–15% 15%
InputCurrent() = 0x0200H 358.4 512 665.6 mA
–30% 30%
INPUT CURRENT OR DISCHARGE CURRENT SENSE AMPLIFIER
VACP/N_OP Input common mode range Voltage on ACP/ACN 4.5 24 V
VSRP/N_OP Output common mode range Voltage on SRP/SRN 14.5 V
IIOUT IOUT Output current 0 40 µA
AIOUT Current sense amplifier gain V(IOUT)/V(SRN-SRP) , 0x12H[15]=1, 0x12H[4]=1 and 0x12H[3]=1 16 V/V
V(IOUT)/V(ACP-ACN), 0x12H[4]=0 and 0x12H[3]=1 40 V/V
VSRN-SRP_OFF Input current amplifier offset voltage 1 mV
VIOUT_ACC Current sense output accuracy V(SRN-SRP) or V(ACP-ACN) = 40.96mV –2% 2%
V(SRN-SRP) or V(ACP-ACN) = 20.48mV –3% 3%
V(SRN-SRP) or V(ACP-ACN) = 10.24mV –10% 10%
V(SRN-SRP) or V(ACP-ACN) = 5.12mV –25% 25%
CIOUT_MAX Maximum output load capacitance For stability with 0 to 1mA load 100 pF
REGN REGULATOR
VREGN_REG REGN Regulator voltage VVCC > 6.5V, VACDET>0.6V (0-50mA load) 5.5 6 6.5 V
IREGN_LIM REGN Current limit VREGN = 0V, VVCC > UVLO, Converter enabled and not in TSHUT 50 75 mA
VREGN = 0V, VVCC > UVLO, Converter disabled or in TSHUT 7 14 mA
CREGN REGN Output capacitor required for stability ILOAD = 100 µA to 50 mA 1 μF
UNDER VOLTAGE LOCKOUT COMPARATOR (UVLO)
VUVLO_VCC Under-voltage rising threshold VVCC rising 3 3.2 3.4 V
Under-voltage hysteresis, falling VVCC falling 400 mV
VUVLO_BAT Under-voltage rising threshold VSRN rising 3 3.3 3.6 V
Under-voltage hysteresis, falling VSRN falling 400 mV
QUIESCENT CURRENT
IBAT_BATFET_ON Standby mode. System powered by battery. BATFET ON.
ISRN+ISRP+IPHASE+IBTST+IACP+IACN+ICMSRC		 VBAT = 12.6V, VSRN >UVLO, BATFET turns on,
ACDET<0.6 V, TJ = –20°C to 85°C,
0x12[15]=1 (low power mode enabled)		 13.3 20 μA
VBAT = 12.6V, VSRN>UVLO, BATFET turns on,
ACDET<0.6 V, TJ = –20°C to 85°C,
0x12[15]=0 (low power mode disabled)		 50 70 μA
ISTANDBY Adapter standby quiescent current,
IVCC+IACP+IACN+ICMSRC		 ACN=ACP=CMSRC=VCC=20 V, VBAT = 12.6V, VACDET> 2.4V,
CELL pull up, TJ = –20°C to 85°C. No switching.		 540 700 µA
IAC_SWLIGHT Adapter current, IVCC+IACP+IACN+ICMSRC ISTANDBY plus supply current in PFM,
200mW output; Reg0x12[10]=0; MOSFET Qg=4 nC;		 1.5 mA
ISTANDBY plus supply current in PFM,
200mW output; Reg0x12[10]=1; MOSFET Qg=4 nC;		 5
IAC_SW Adapter current, IVCC+IACP+IACN+ICMSRC Charge enable, 800kHz switching frequency MOSFET Qg=4 nC 10 mA
ACOK COMPARATOR
VACOK_RISE ACOK Rising threshold VVCC>UVLO, VACDET rising 2.376 2.4 2.424 V
VACOK_FALL_HYS ACOK Falling hysteresis VVCC>UVLO, VACDET falling 35 55 75 mV
VWAKEUP_RISE WAKEUP Detect rising threshold VVCC>UVLO, VACDET rising 0.52 0.6 V
VWAKEUP_FALL WAKEUP Detect falling threshold VVCC>UVLO, VACDET falling 0.35 0.46 V
VCC to SRN COMPARATOR (VCC_SRN), SLEEP
VVCC-SRN_FALL VCC-SRN Falling threshold VVCC falling towards VSRN 120 250 375 mV
VVCC-SRN _RHYS VCC-SRN Rising hysteresis VVCC rising above VSRN 300 mV
INPUT OVER-CURRENT COMPARATOR
ACOC ACP to ACN Rising Threshold, respect to input current(). ChargeOption() bit [7] = 1 330% IDPM
ACOC floor 50 mV
ACOC ceiling 180 mV
LIGHT LOAD COMPARATOR
ACP to ACN Falling Threshold, average Converter CCM-DCM, current decrease 1.25 mV
ACP to ACN Rising Threshold, average 2.5 mV
CONVERTER OVER-CURRENT COMPARATOR (ILIM_HI), CYCLE-BY-CYCLE
ILIM_HI Converter over current limit, measure GND-PH Chargeoption() bit [6] =0 250 mV
Chargeoption() bit [6] =1 (default) 350 mV
CONVERTER UNDER-CURRENT COMPARATOR (ILIM_LOW) , CYCLE-BY-CYCLE
Converter over current limit, measure GND-PH –2 0 6 mV
INPUT OVER-VOLTAGE (ACOVP)
VACOVP VCC Over-Voltage Rising Threshold VCC rising 24 26 28 V
VACOV_HYS VCC Over-Voltage Falling Hysteresis VCC falling 1 V
BAT OVER-VOLTAGE COMPARATOR (BAT_OVP)
VOVP_RISE Over-voltage rising threshold as percentage of VBAT_REG VSRN rising 102.5% 104% 106%
VOVP_FALL Over-voltage falling threshold as percentage of VBAT_REG VSRN falling 102%
Discharge current during OVP, SRP pin Charge enable, BATFET ON 4 mA
SYSTEM OVER-VOLTAGE COMPARATOR (SYS_OVP)
VSYSOVP_RISE_3S 3S System over-voltage rising threshold VSRN rising, chargeoption bit[12]=0 default 15.1 V
VSRN rising, chargeoption bit[12]=1 17.0
VSYSOVP_FALL_3S 3S System over-voltage falling threshold VSRN falling 13.2 V
VSYSOVP_RISE_2S 2S System over-voltage rising threshold VSRN rising, chargeoption bit[12]=0 default 10.1 V
VSRN rising, chargeoption bit[12]=1 11.3
VSYSOVP_FALL_2S 2S System over-voltage falling threshold VSRN falling 8.8 V
Discharge current during OVP 4 mA
THERMAL SHUTDOWN COMPARATOR (TSHUT)
TSHUT Thermal shutdown rising temperature Temperature rising 155 °C
TSHUT_HYS Thermal shutdown hysteresis, falling Temperature falling 20 °C
LOGIC INPUT (SDA, SCL)
VIN_ LO Input low threshold 0.8 V
VIN_ HI Input high threshold 2.1 V
IIN_ LEAK Input bias current V = 7 V –1 1 μA
LOGIC OUTPUT OPEN DRAIN (ACOK, SDA)
VOUT_ LO Output saturation voltage 5 mA drain current 500 mV
IOUT_ LEAK Leakage current V = 7 V –1 1 μA
ANALOG INPUT (ACDET)
IIN_ LEAK Input bias current V = 7 V –1 1 μA
Offset –10 10 mV
ANALOG INPUT (CELL)
GND 1.0 V
Float (2S setting) 1.2 1.8 V
High (3S setting) 2.5 V
Internal pull up resistor to REGN 405 kΩ
Internal pull down resistor to GND 141 kΩ
PWM OSCILLATOR
FSW PWM Switching frequency ChargeOption () bit [9:8] = 00 –10% 600 10% kHz
ChargeOption() bit [9:8] = 01 (Default) –10% 800 10% kHz
ChargeOption() bit [9:8] = 10 –10% 1000 10% kHz
FSW_min Audio frequency limit, PFM ChargeOption() bit [10] = 1 40 kHz
ACFET GATE DRIVER (ACDRV)
IACFET ACDRV Charge pump current limit 40 60 μA
VACFET Gate drive voltage on ACFET VACDRV – VCMSRC when VVCC > UVLO 5.5 6.1 6.7 V
RACDRV_LOAD Minimum load resistance between ACDRV and CMSRC 500 kΩ
RACDRV_OFF ACDRV Turn-off resistance I = 30 μA 5 6.2 7.4 kΩ
VACFET_LOW ACDRV Turn-off when Vgs voltage is lower than VACFET (Specified by design) The voltage below VACFET 0.2 V
BATTERY FET GATE DRIVER (BATDRV)
RDS_BAT_OFF BATFET Turn-off resistance 100µA current into BATDRV 2 kΩ
RDS_BAT_ON BATFET Turn-on resistance 100µA current from BATDRV 5 kΩ
VBATDRV_REG BATFET Drive voltage VBATDRV_REG =VSRN – VBATDRV
when VAVCC > 5 V and BATFET is on		 4.2 8 V
PWM HIGH SIDE DRIVER (HIDRV)
RDS_HI_ON High side driver turn-on resistance VBTST – VPH = 5.5 V, I = 10 mA 4 5.5 Ω
RDS_HI_OFF High side driver turn-off resistance VBTST – VPH = 5.5 V, I = 10 mA 0.65 1.3 Ω
VBTST_REFRESH Bootstrap refresh comparator threshold voltage VBTST – VPH when low side refresh pulse is requested 3.85 4.15 4.7 V
PWM LOW SIDE DRIVER (LODRV)
RDS_LO_ON Low side driver turn-on resistance VREGN=6V, I=10mA 4 6.2 Ω
RDS_LO_OFF Low side driver turn-off resistance VREGN=6V, I=10mA 0.9 1.4 Ω
INTERNAL SOFT START
ISTEP Soft start current step In CCM mode 10 mΩ current sensing resistor 64 mA

5.6 Timing Requirements

6V ≤ VVCC ≤ 24V, –20°C ≤ TJ ≤ 125°C, typical values are at TA = 25°C, with respect to GND (unless otherwise noted)
PARAMETER TEST CONDITION MIN TYP MAX UNIT
ACOK COMPARATOR
VACOK_RISE_DEG ACOK Rising deglitch (Specified by design) VVCC>UVLO, VACDET rising above 2.4V 2 3 ms
VCC to SRN COMPARATOR (VCC_SRN), SLEEP
VCC-SRN falling delay VCC falling towards VSRN 95 160 237 µs
Resume time VVCC rising above VSRN 0.76 1.28 1.9 ms
INPUT OVER-CURRENT COMPARATOR
Relax time, No latch. 300 ms
INPUT OVER-VOLTAGE (ACOVP)
Rising deglitch VCC rising 0.1 ms
Falling deglitch VCC falling 1 ms
BAT OVER-VOLTAGE COMPARATOR (BAT_OVP)
Over voltage deglitch time to fully turn-off BATFET 1 ms
SYSTEM OVER-VOLTAGE COMPARATOR (SYS_OVP)
tSYSOVP_DEG System over-voltage deglitch time to turn-off ACDRV 24 µs
THERMAL SHUTDOWN COMPARATOR (TSHUT)
Rising deglitch 100 µs
Falling deglitch 10 ms
ANALOG INPUT (CELL)
Allowed max delay time to config CELL at POR 72 100 120 ms
PWM DRIVER TIMING
tLOW_HIGH Driver dead time from low side to high side 20 ns
tHIGH_LOW Driver dead time from high side to low side 20 ns
INTERNAL SOFT START
Soft start current step time 24 μs

5.7 SMBus Timing Characteristics

4.5 V ≤ V(VCC) ≤ 24 V, 0°C ≤ TJ ≤125°C, typical values are at TA = 25°C, with respect to GND (unless otherwise noted)
MIN TYP MAX UNIT
tR SCLK/SDATA rise time 1 µs
tF SCLK/SDATA fall time 300 ns
tW(H) SCLK pulse width high 4 50 µs
tW(L) SCLK Pulse Width Low 4.7 µs
tSU(STA) Setup time for START condition 4.7 µs
tH(STA) START condition hold time after which first clock pulse is generated 4 µs
tSU(DAT) Data setup time 250 ns
tH(DAT) Data hold time 300 ns
tSU(STOP) Setup time for STOP condition 4 µs
t(BUF) Bus free time between START and STOP condition 4.7 µs
FS(CL) Clock Frequency 10 100 kHz
HOST COMMUNICATION FAILURE
ttimeout SMBus bus release timeout (1) 25 35 ms
tBOOT Deglitch for watchdog reset signal 10 ms
tWDI Watchdog timeout period, ChargeOption() bit [14:13] = 01(2) 35 44 53 s
Watchdog timeout period, ChargeOption() bit [14:13] = 10 (2) 70 88 105
Watchdog timeout period, ChargeOption() bit [14:13] = 11 (2) (Default) 140 175 210
(1) Devices participating in a transfer will timeout when any clock low exceeds the 25ms minimum timeout period. Devices that have detected a timeout condition must reset the communication no later than the 35ms maximum timeout period. Both a master and a slave must adhere to the maximum value specified as it incorporates the cumulative stretch limit for both a master (10ms) and a slave (25ms).
(2) User can adjust threshold via SMBus ChargeOption() REG0x12.
bq24715 smbus_tim_lusbd1.gif Figure 1. SMBus Communication Timing Waveforms
bq24715 smbus_write-timing_lusbd1.gif Figure 2. SMBus Writing Timing
bq24715 smbus_read-timing_lusbd1.gif Figure 3. SMBus Read Timing

5.8 Typical Characteristics

bq24715 fig13_light-load_efficiency_24715_lusbd1.gif
VIN = 19.5 V
Figure 4. Light Load Efficiency vs. System Current
bq24715 fig14_heavy-load_efficiency_24715_lusbd1.gif
VIN = 19.5 V
Figure 5. Heavy Load Efficiency vs. System Current

 
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